Significant effects of the anion on the catalytic behaviour of sulfonic acid-functionalized ionic liquids in transesterification reactions – A combined electrochemical/catalytic study

Protic ionic liquids for sustainable uses

“…The role of increasing the Brønsted acidity of PILs by choice of cation-anion interactions has been discussed by Martini and co-workers. 96 By combining cyclic voltammetry with cata-lytic reactions, they concluded that sulfonic-acid-functionalised cations with [HSO 4 ] − anions were simply acting as a source of free sulfuric acid delivered by reverse auto-pyrolysis, and this was catalysing the esterification. Although it is yet to be confirmed, the use of amide-based PILs could also be acting as potential reservoirs for neat acids and this warrants further investigation.…”